The Vatican said it was launching the channel to broaden Benedict's audience while also giving the Holy See better control over the papal image online.

In his inaugural foray, Benedict welcomed viewers to this "great family that knows no borders" and said he hoped they would "feel involved in this great dialogue of truth."

The site, www.youtube.com/vaticanit, was launched the same day the pontiff praised as a "gift to humanity" the benefits of social networking sites such as Facebook and MySpace in forging friendships and understanding.

But Benedict also warned that virtual socializing had its risks, saying "obsessive" online networking could isolate people from real social interaction and broaden the digital divide by further marginalizing people.

And in his message for the World Day of Communications, he urged producers of new media to ensure that the content respected human dignity and the "goodness and intimacy of human sexuality."

The 81-year-old pope has been extremely wary of new media and their effect on society, warning about what he has called the tendency of entertainment media, in particular, to trivialize sex and promote violence.

But Monsignor Claudio Maria Celli, who heads the Vatican's social communications office, said the pope fully approved of the Vatican YouTube channel, saying Benedict was "a man of dialogue" who wanted to engage with people wherever they were.

"It's true that not all of humanity is found on YouTube, but millions of people meet on YouTube," Celli told reporters.

Benedict is joining the White House, which launched its own YouTube channel after Obama's inauguration day, as well as Queen Elizabeth II, who went online with her royal YouTube channel in December 2007.

Celli said the Vatican was launching the channel in part to have some control over the pontiff's image, which he said already was being used on sites respectful of the papacy and not.

"It's undeniable that certain images are already circulating," Celli said. While there is little the Vatican can do legally to shut down blasphemous or pornographic sites that use the papal or other Church images, he said it can at least control the content of what it puts up on its own channel.

The Vatican spokesman, the Rev. Federico Lombardi, said the Vatican hoped that YouTube owner Google, Inc., would help the Holy See determine where Vatican images are being used so that it can better protect its own images.

He said no money exchanged hands to launch the channel and that the Vatican wouldn't earn anything with publicity. "We didn't pay a cent to Google," he said, adding that the channel was the Vatican's "offer" to the world.